UNDERSTANDING COLLIE EYE ANOMALY

UNDERSTANDING COLLIE EYE ANOMALY

Kathy Moll – Deep River Collies

Collie Eye Anomaly (CEA) is a congenital, inherited condition of several breeds (most especially the collie). Collie puppies should be checked for CEA by a Veterinary Ophthalmologist before they are placed in new homes.

CEA affects 85% to 90% of collies. Of the 10% to 15% of the unaffected collie population, fewer than 50% are normal eyed/non-carriers. Most CEA has not proven to be vision impairing in clinical studies, so owners will rarely see any discernable difference between collies with CEA and those who are not affected (normal eyed collies). Exceptions are explained below.

Collies with the least serious form of CEA have what is called choroidal hypoplasia, chorioretinal dysplasia, or chorioretinal change. These three terms are used interchangeably and describe the same condition – a pale, thin area in the choroid – both eyes. Collies with this mildest form of collie eye retain normal vision throughout life. This form is present in about 75% of collies with CEA. The reason for checking litters by 8 weeks of age is that some collie puppies have such a small pale area that they can appear to be normal eyed shortly after 8 weeks. These are typically described by breeders as “go-normals.” Even with sophisticated ophthalmologic equipment, these collies will appear as normal (no collie eye) just as true normal collies.

Coloboma and staphyloma are more serious forms of CEA. These may occur in only one eye or in both eyes. Colobomas are seen at or near the optic nerve as a cleft or out pouching. Staphylomas appear as an area of thinning in the sclera, adjacent to the choroid. Small to moderate clefts rarely change and do not seem to affect the collie’s visual acuity. Therefore, most collies with this problem make suitable companions and have no problems throughout life. Around 15% to 20% of collies have this form of CEA, usually in one eye but occasionally in both eyes. In rare cases a large coloboma may be present which presents the risk of causing a serious problem – a tear in the optic nerve/disc. Vision impairment and eventual blindness may occur in an eye with a large coloboma.

Fewer than 10% of collies affected with CEA have the most serious form of the disease – retinal detachment. This blindness-causing defect (partial or total) usually occurs in one eye but may occur in both. Puppy eye checks reveal this serious defect. Collies who are detached in one eye can lead relatively normal lives.

Genetically, CEA as a syndrome is a simple recessive trait; however, its degree of expression is more complex. At present the modifiers that control the expression of CEA are not known. The good news is that they may be identified with further study now that CEA has been located to chromosome 37.

10 Responses to UNDERSTANDING COLLIE EYE ANOMALY

Does CEA STILL affect that high of a percentage of the Collie population? About the year 2000, CERF stated that the number of Collies affected with CEA had dropped to about 50% — however this number was for the number of animals checked for CERF, as opposed to ALL eye checks done by ALL ophthalmologists since not everyone CERFs their dogs.

You may be right, Cindy. I kept the old stats because my collies when checked at 7 to 8 weeks seem to maintain at about 15% normal, 80% hypoplasia with about half of those “go-normals” and 5% coloboma. I’ve had only 2 puppies with colobomas in both eyes & 2 puppies that were detached in one eye since I started breeding in 1978, so statistically not measureable. I don’t send in my CERF forms even on the normal-eyed puppies.

Hi!, Since we bought a pupp with retinal detachment, when we started looking for another one we specifically asked for a normal eyed collie. You would be amazed by the answers we got. Some respected breeders told me that without CEA you couldn’t get the “almond shaped eyes” mentioned in the standard. Others told me that I wouldnt find a normal eyed collie that would be “up to standard”. Unfortunately they where right, I dind’t like the features of the normal eyed pupps I was offered. My conclusion was that it may be almost imposible to buy a normal eyed collie with Show qualities. I really hope that breeders at least considered keeping the normal eyed carriers instead of the affected ones to increase the chances of normal eyed pupps. Retinal detachments are really sad and I wish no one has to dealt with it. Regards
Mati

Hi Mati,
I’m so sorry to hear about your experiences!
You actually can get correct eye shape and placement wirh normal eyes. Here’s my theory. Back when collie eye was first discovered in our breed in the late ’60’s, some breeders went way overboard and euthanized collies with any CEA, even hypoplasia. Some folks started breeding mainly for normal eyes and didn’t put the time into keeping type and temperament. The result set the overall quality of normal eyed collies back quite a bit IMHO. If you’re rational about eye checks, you “don’t throw the baby out with the bath water.” I’ve had some beautiful champions with normal eyes, not as many as with mild hypoplasia, but we’re always working on it! Breeding for beauty, temperament & health is a difficult balancing act, so it takes time to reach all your goals!

Thanks so much for your answer, I had collies all my life but started with the serius showing just a couple of years ago, there’s so much to learn. Regarding our girl with the CEA and retinal detachment (fortunatelly in one eye), do you advise us to breed her? We haven’t and at first were not intending to, but she is so sound and has such a wonderful temperament that she is making us reconsider. I know I should find a non-carrier for her, but even with that I cannot be sure of her pupps pupps… her grandchildren. Please let me know what you think about it. Regards, Matis

I would not breed her regardless of her other good qualities. A retinal detachment is way too serious a problem. I have on 3 occassions over 35 years bred a collie with a tiny coloboma with no harm. However, the one time I bred a moderate coloboma to a normal – I had 2 normals, 1 hypoplasia & 3 colobomas. I would never do that again, and the bitch I bred was a multiple Group placing rough who finished easily. Mine was also VERY sound with a great temperament. Even with a normal/non-carrier, you run great risks for the future and would have to continue that process and have all the offspring tested for carrier status, probably for several generations.

We have 2 rescued collies. Our 11 year old is a blue-eyed sable merle, and the younger one is a “regular” sable. However, our newest guy turns out to have serious CEA, including being totally blind in his left eye, although fairly minimal CEA effects in his right eye. He had been raised on a family farm and when they outgrew him they put him on craigslist. From there he went into a rescue. I was the first person to notice that he had vision problems, and I cringe to think of how he was treated when he was younger, or indeed what else might have become of him if he hadn’t been rescued. He’s always banging into something, and he can “spook” easily when approached from his blind side. He is truly a sweet, velcro collie, with a huge heart and spirit. His vision problems break our hearts.

When we had him evaluated by the ophthalmologist, we were surprised to learn his professional knowledge that CEA is present (to some degree) in virtually all North American Collies and shelties. This opth vet (who has had a long career) told us that over his entire career he has seen perhaps only 1-2 collies that did not have some degree of CEA. He also said that people have stopped bringing their pups in to be checked for CEA. That means that probably a lot of NA people are breeding affected dogs without even knowing the status of their eyes. He also told us that in Britain virtually all collies/shelties are CEA-free. So, if one really wants CEA-free breeding stock, it would seem that importing from Britain would be the way to go to get our North American stock back on track. Personally, I believe that our American culture has placed way too much value on “looks”, to the detriment of our dogs’ health (eye health included).

I’m so sorry to hear about your collie with the retinal detachment. In defense of the rescue organization, if it’s like our CRC the majority of the collies we get do not come with eye checks. Most of from “breeders” who likely don’t know there is such a thing and wouldn’t spend the money to test even if they did. They’re not breeding for looks; they’re breeding for money. That’s usually their only motive.

As a conscientious breeder, I do testing, including eye exams before I sell puppies. I have a contract requiring that a collie purchased from me comes back to me if the owner can no longer care for the collie.

My ophthalmologist does not agree with the one you went to see. First, there are normal eyed collies & shelties in the US, and there are affected collies & shelties in the UK. Here are 2 recent articles on CEA for you to read to find out more:

I quote from a sheltie breeder in the UK below who is working to eliminate health problems. Eyes are one thing; like people, dogs may fall victim to a number of genetic diseases, some much more serious than hypoplasia, the form of collie eye that most have. It causes no clinical signs. You have to work on everything – all health problems (not just eye checks), temperament, working ability, and appearance. Here’s what the sheltie breeder from the UK says:

“Unfortunately, the incidence of CEA in Rough / Smooth Collies & Shelties is still quite high in the UK, with Border Collies being less affected. The Go Normal status is a great threat to any responsible breeding program, but personally I would consider using an affected dog / bitch if I felt their other attributes could not be found elsewhere / I considered they were the best advantage for my breeding strategy. I would ensure they were mated to a clear dog / bitch (preferably genetically clear, but currently the only way to assume a dog is clear if through large numbers of unaffected puppies – very hard for a bitch / little used stud) & would endeavor to breed only clear (although carrier) pups. An affected dog is genetically affected regardless of whether slightly or severely. It is a shame to lose a marvelous bloodline for just one factor – especially when that factor does not cause (or does so rarely as to make it highly unlikely) any apparent visual defects in the dog. Although we are trying our best to establish a CEA clear line, I would be more concerned with hip dysplasia or poor temperaments in our shelties.”